Sulfolane is widely used as an industrial solvent, especially in the extraction of aromatic hydrocarbons from hydrocarbon mixtures and to purify natural gas. This process is sometimes referred to as “extractive desulfurization,” particularly where sulfolane is used to reduce the concentration of sulfur-containing compounds. For example, in one such extractive desulfurization process, sulfolane is used to purify natural gas by removing H2S, CO2, COS and mercaptans from natural gas. Sulfolane is also effective in separating high purity aromatic compounds from hydrocarbon mixtures using liquid-liquid extraction. This process is widely used in refineries and the petrochemical industry. Because sulfolane is one of the most efficient industrial solvents for purifying aromatics, the process operates at a relatively low solvent-to-feed ratio, making sulfolane relatively cost effective compared to similar-purpose solvents. In addition, it is selective in a range that compliments distillation. Thus, distillation may be used to compliment sulfolane extraction. The resulting hydrocarbons are low in sulfur compounds. But because sulfolane itself contains sulfur, its content in the purified hydrocarbon needs to be reduced, e.g., to meet ever more stringent fuel standards.
Sulfolane removal systems are well known. Nevertheless removal of residual sulfolane from hydrocarbon streams remains challenging, particularly to levels recited in motor gasoline standards. Thus, a method of removing sulfolane from hydrocarbon streams, such as motor fuels, that also balances capital cost and operational efficiencies, particularly where such a method can be relatively easily incorporated into exiting sulfolane removal processes, would be useful.